In the original DOS version of Descent, the Spreadfire cannon consumes the same amount of energy that the normal laser does: 1/2 point per shot on Hotshot difficulty and up. However, in the current beta of D1X-Rebirth, this cannon consumes twice as much energy.

The Spreadfire cannon consumes the correct amount of energy in D2X-Rebirth (which is, again, the same amount as the laser).